lowered cost.
Currently, this is a direct port of the logic implementing
isInstructionFree in CodeMetrics. The hope is that the interface can be
improved (f.ex. supporting un-formed instruction queries) and the
implementation abstracted so that as we have test cases and target
knowledge we can expose increasingly accurate heuristics to clients.
I'll start switching existing consumers over and kill off the routine in
CodeMetrics in subsequent commits.
llvm-svn: 172998
It is not possible to distinguish 3r instructions from 2r / rus instructions
using only the fixed bits. Therefore if an instruction doesn't match the
2r / rus format try to decode it as a 3r instruction before returning Fail.
llvm-svn: 172984
The optimization handles esoteric cases but adds a lot of complexity both to the X86 backend and to other backends.
This optimization disables an important canonicalization of chains of SEXT nodes and makes SEXT and ZEXT asymmetrical.
Disabling the canonicalization of consecutive SEXT nodes into a single node disables other DAG optimizations that assume
that there is only one SEXT node. The AVX mask optimizations is one example. Additionally this optimization does not update the cost model.
llvm-svn: 172968
I also changed the name of a variable in IRBuilder::CreateFPExtOrFPTrunc to
match the names used in its two matching brethern as well.
llvm-svn: 172967
We ignore the cpu frontend and focus on pipeline utilization. We do this because we
don't have a good way to estimate the loop body size at the IR level.
llvm-svn: 172964
This implies changing method documentation from the following style:
/// MethodName - Method description...
to
/// \brief Method description...
ala the LLVM Style Guide.
llvm-svn: 172959
This method serves an analogous purpose to CreateZExtOrTrunc/CreateSExtOrTrunc
but for floating point types.
In detail, it provides a manner when one is handling conversions of floating
point types of automatically selecting fpext, fptrunc, or identity depending on
the relative bitsize of the source and destination types.
llvm-svn: 172957
This change also removes a bunch of boilerplate and stuffing which made
it unnecessarily hard to navigate and see the comparatively miniscule
actual content that was added to this document during the 3.2
development period (or maybe even sticking around from earlier
releases...).
The new organization (a flat list) optimizes for making it easy for
people who know about changes to add them to the document. It's
completely trivial for anyone with basic knowledge of LLVM to come in
later (such as when preparing for the actual release) and cluster any
changes into logical groups. However, I have left some comments
indicating how to add larger descriptions, if someone is feeling
adventurous ;)
Hopefully this organization will highlight how little effort is being
put into producing accurate, high-quality release notes, prompting a
corresponding improvement for the 3.3 release.
I have preserved the changes to this document that are not present
in the 3.2 release notes. There were only two... I'm pretty sure we've
been busier than that... (version control shows +213347/-173656 raw
lines just in the LLVM repo since the 3.2 release).
llvm-svn: 172954
